SEDGE FAMILY 



263 



4. Eleocharis obtusa (W'illd.) Schultes. 

 Blunt Spike-rush. Fig. 627. 



Scirptis obtusiis Willd. Enum. 76. 1809. 



Eleocharis obtusa Schultes, Maiit. 2: 89. 1824. 



E. ovata gigantca Clarke; Britton, Journ. N. Y. Mi- 

 cros. Soc. 5: 103. Hyponym. 1889. 



E. obtusa gigantca Fernald, Proc. Am. Acad. 34: 493. 

 1899. 



Annual with fibrous roots. Culms slender, 

 tufted, 1-5 dm. long; upper sheath 1-toothed; 

 spikelet ovoid to ovoid-oblong, obtuse, 2-13 mm. 

 long, densely many-flowered; scales obovate to 

 nearly orbicular, brown, obtuse, with scarious 

 margins ; style 2-cleft ; achene compressed, 

 obovate, pale brown, smooth, shining, about 1 

 mm. long; tubercle deltoid, acute, about one- 

 third as long as the achene and nearly or quite 

 as broad as its top; bristles usually longer than 

 the achene. 



Muddy places. Transition Zone; Siskiyou County, 

 California, to British Columbia; Texas to Florida, Min- 

 nesota and Cape Breton Island. Type locality: North 

 America. The species was formerly included in E. 

 ovata, and as such recorded by me from Oregon. 



5. Eleocharis engelmanni Steud. 

 Engelmann's Spike-rush. Fig. 628. 



Eleocharis Engelmanni Steud. Syn. PI. Cyp. 79. 1855. 

 Eleocharis monticola Fernald, Proc. Am. Acad. 34: 496. 1899. 



Annual, similar to the preceding species. Upper 

 sheath obliquely truncate or 1-toothed ; spikelet 

 oblong-cylindric or ovoid-cylindric, obtuse or sub- 

 acute, 4-16 mm. long, 2-3 mm. in diameter, many- 

 flowered ; scales pale brown with a green midvein 

 and narrow scarious margins, ovate, obtuse, decidu- 

 ous; style 2-cleft or sometimes 3-cleft; bristles about 

 6, not longer than the achene ; achene broadly 

 obovate, brown, smooth, lenticular ; tubercle broad, 

 low, covering the top of the achene, less than one- 

 fourth its length. 



Muddy places, Transition Zone; Washington to Mariposa 

 County, California, east to Idaho, Manitoba, South Dakota, 

 Texas, Indiana, Massachusetts, and New Jersey. Ty];e lo- 

 cality: St. Louis, Missouri. Referred by S. Watson to E. 

 obtusa. 



6. Eleocharis palustris ( L. ) R. & S. 

 Creeping Spike-rush. Fig. 629. 



Scirpus palustris L. Sp. PI. 47. 1753. 

 Eleocharis palustris R. & S. Syst. 2: 151. 1817. 



Perennial by horizontal rootstocks ; culms terete or 

 somewhat compressed, striate, 0.3-1.6 m. tall. Basal 

 sheaths brown, rarely bearing a short blade, the upper 

 one obliquely truncate ; spikelet ovoid-cylindric. 6-25 

 mm. long. 3-4 mm. in diameter, many-flowered, thicker 

 than the culm ; scales ovate-oblong or ovate-lanceolate, 

 purplish brown with scarious margin and a green mid- 

 vein, or pale green all over; bristles usually 4, slender, 

 retrorsely barbed, longer than the achene and tubercle, 

 or sometimes wanting ; stamens 2-3 ; style mostly 

 2-cleft ; achene lenticular, smooth, yellow, over 1 mm. 

 long; tubercle conic-triangular, constricted at the base, 

 flattened, one-fourth to one-half as long as the achene. 



Wet grounds and in water, Sonoran to Canadian Zones; southern California to Alaska, east to Labrador 

 and Florida. Europe and Asia. Type locality: Europe. Consists of many races, the culms slender to stout, 

 the tubercle narrow or quite broad. 



